Forced air circulation refrigeration system



0a. 6, 1942. c. A. L. MERZ 2,297,970

FORGED AIR CIRCULATION REFRIGERATION SYSTEM Filed May 27, 1940 INVENTOR Patented Oct. 6, 1942 FORCED AIR CIRCULATION REFRIGERk- TION SYSTEM Catherine A. L. Merl, Chicago, Ill., assignor to Flow Controls, Inc., Chicago, 111.

Application May 21, 1940, Serial No. 337,412

1 Claim.

The present invention relates to the cooling of compartments through the walls of which a heat flow exists due to a difference in temperatur'e between a high exterior temperature and a low interior temperature.

Specifically, the invention relates to maintaining a pulsating circulation of air over the exterior surfaces of a cooling unit through which a volatile refrigerant is circulated and thereby extracts heat from the pulsatory circulated air.

This pulsating circulation of the air, over the exterior surfaces of the cooling unit, tends to set up a pulsating circulation of the air within the cooled compartment, from which certain incidental advantages are obtained.

Up to the present invention, it has been customary to maintain a definite continuous circulation of air over the exterior surfaces of a cooling unit. This generally results in a definite pattern of the air circulation within the cooled compartment. Such definite pattern of air circulation usually results in one or more points within the compartment having a condition of stagnant air. If meats, or other similar hydrous products are stored at those points, their surfaces tend to slime and present an unsalable appearance. Such products might be stored at other points within such compartment, and due to the continuous circulation of cooled and dehydrated (within limits) air, the surfaces of such products might become excessively dehydrated, which usually accompanied by a surface darkening, results in loss of weight and also an unpalatable appearance.

An object, of the present invention, is to improve the cooling characteristics of an air circulation in a cooled compartment.

Another object, of the present invention, is to eliminate stagnant air points within a compartment cooled by a forced air circulation.

A further object, of the present invention, is to provide a greater moisture recovery, from the frosted surfaces of the cooling unit and to a forced air circulation, over such surfaces, during the refrigerant circulation off-time cycle.

A still further object, of the present invention, is to provide a cooled air circulation of perfodic variation in both volume and absolute humidity.

The drawing shows a diagrammatic view, partly in section, of a compartment cooled by means of a refrigerating unit controlled in accordance with the invention.

Referring to the drawing:

A compartment 2 contains a forced air circulation cooling unit 3 comprising a casing 8 in which is placed a cooling coil 5 comprised of a nested and series circulated refrigerant conduit 6 upon which are mounted in spaced relationship a plurality of metallic fin plates 1 for the purpose of increasing the effective heat transfer surface presented to an air circulation thereover by means of the fan 8 driven by the electric motor 9 energized by the electrical conduits l0 and II.

The refrigerant conduit 6 is fed with refrigerant by means of the expansion valve I2 to which connects the high pressure or liquid refrigerant conduit l3, which in turn usually connects to the discharge side of a condenser, not shown.

The outlet ll, of the refrigerant conduit 6, connects to a suction conduit I5, usually connected to the suction side of a compressor, not shown, which serves to evacuate vaporized refrigerant from the conduit 6 and compress the same into the aforementioned condenser, wherein it becomes liquefied due to the rejection of heat.

So far, all of the elements comprise a conventional refrigerating system, in like part, and the compressor aforementioned might, as usual, operate in on-time cycle andoff-time cycle.

During the off-time cycle, the frost previously deposited upon the exterior surfaces of the conduit 6 and the fin plates 1, tends to melt, and the casing I is provided with a drain pipe I, usually connected to a sewer.

An electric circuit interrupter timer l1, generally denoted in the electrical industry as a flasher, and hereinafter so designated, comprises an insulator block I! having projecting lugs 19 and 20 to which are fastened a thermostatic bimetallic arm 2| and a contactor block 22, respectively, by means of the binding post screws 23 and 24, which also serve to clamp the electrical conductors 25 and II, respectively.

Mounted upon the free end of the thermostatic bimetallic ann 2| is a contact point 26, which successively makes and breaks contact with the contact screw 21, which is in screw-threaded engagement with the contactor block 22, so it may be adjusted in an upward or downward position for the purpose subsequently described.

In operation, the electric conduits l0 and 25 are energized by a suitable source of energy, and the contact screw 21 is moved into the downward position till it contacts the contact point" of the birnetaliic arm 2 I, at which time the electric current flow is established in the electric circuit comprising the conductor 25, the bimetallic arm 2|, the contact point 26, the contact screw 21,

' sulting in an air flow I ductor I.

Since the fan motor 8 is now energized, it readily comes to full speed, at which time the maximum air fiow velocity, through the cooling unit 3, occurs. After a certain lapse of time, the flow of electric current, through the bimetallic arm 2|, heats it sufliciently, so that, due to its bimetallism, it bends away from the contact screw 21 and thereby breaks the electric circuit between the contact point 26 and the contact screw 21, at which time the fan motor 8, no longer energized, drops in speed and consequently the air flow is reduced accordingly.

The contact screw 21 is made adjustable so that it may exert an increasing force upon the bimetallic arm 2| and thereby vary the number and/or also the time duration of the electrical impulses exerted upon the fan motor 9.

With the system in operation the fan motor 9 is successively energized and de-energized, re-

through the cooling unit 3 of successively high and low velocities respec- .I'his varying air flow velocity results in tively.

a pulsating air circulation, within the cooled compartment 2, which gives optimum conditions for the preservation of stored meats and the like.

While I have show diagrammatically, a certain type of flasher, the function thereof may be derived from the usage 01' any suitable electrical timer interrupter, of which numerous types are available upon the open market.

While the drawing and specification relate to a particular embodiment of the invention, it is to be understood that many variations may be employed without departing from the spirit and scope of the invention, which is to be limited only to the hereto appended claim.

I claim:

The method of operating an electric motor serving to drive fan means for the continuous circulation of air over the exterior surfaces of a cooling unit and thereby cooling such air, which comprises periodically and successively energizing and de-energizing said motor for comparatively short periods of time.

CATHERINE A. L. MERZ. 

